I like posting as I go too, because sometimes the comments you get in reviews and people's reactions can give you a heads up if something's not working. It allows you to catch some of those plot holes earlier on. Plus, like Julie said, it's more motivating.
I am definitely an outliner. But I hate it when things don't all end up coming together at the end. If things are left unanswered I want to shoot someone. (Hence the reason I couldn't watch LOST after season two. lol) I start with beginning, act 1 break, midpoint, act 2 break, and end. Then I figure out all sub plots and plot them in the outline. But I never really plot out any specific scenes because you just can't tell how it's all going to happen until your characters get involved and take over for you. But there are a million ways to accomplish everything that needs to happen. I find that when my outline does change, the same goals are always achieved, it's just how they happen that's different.
For some reason I don't think I just made any sense. Sorry. I know what 'm trying to say, just having a hard time putting it into words.
So, to add back to the original question, (it's nice not to be the hijacker for once!) Is your fanfic reading niche different from your book reading niche?
I tend to read pretty much the same types of fan fics as I do books.
I've found that it's a little different with writing. I write differently when I'm writing fan fic then I do when I'm writing original fiction. Maybe it's because I have specific characters I have to work with. I always feel like I have a lot less freedom when writing fan fic so I stay within some specific guidelines. But I can go anywhere I want in original fiction.